AIM OF THE STUDY: The study is aimed at identifying the key ingredients of papaya leaf extract and elucidate the mechanism (s) of action of the identified potent component in mitigating thrombocytopenia (Thp).
MATERIALS AND METHODS: C. papaya leaf juice was subjected for sequential fractionation to identify the anti-thrombocytopenic phytochemicals. In vivo, stable thrombocytopenia was induced by subcutaneous injection of 70 mg/kg cyclophosphamide (Cyp). After induction, rats were treated with 200 and 400 mg/kg body weight papaya leaf juice and with identified fractions for 14 days. Serum thrombopoietin level was estimated using ELISA. CD110/cMpl, a receptor for thrombopoietin on platelets was measured by western blotting.
RESULTS: Administration of cyclophosphamide for 6 days induced thrombocytopenia (210.4 ± 14.2 × 103 cells/μL) in rats. Treating thrombocytopenic rats with papaya leaf juice and butanol fraction for 14 days significantly increased the platelet count to 1073.50 ± 29.6 and 1189.80 ± 36.5 × 103 cells/μL, respectively. C.papaya extracts normalized the elevated bleeding and clotting time and decreased oxidative markers by increasing endogenous antioxidants. A marginal increase in the serum thrombopoietin (TPO) level was observed in Cyp treated group compared to normal and treatment groups. Low expression of CD110/cMpl receptor found in Cyp treated group was enhanced by C. papaya extracts (CPJ) and CPJ-BT. Furthermore, examination of the morphology of bone marrow megakaryocytes, histopathology of liver and kidneys revealed the ability of CPJ and fractions in mitigating Cyp-induced thrombocytopenia in rats.
CONCLUSION: C. papaya leaf juice enhances the platelet count in chemotherapy-induced thrombocytopenia by increasing the expression of CD110 receptor on the megakaryocytes. Hence, activating CD110 receptor might be a viable strategy to increase the platelet production in individuals suffering from thrombocytopenia.
AIM OF THE STUDY: A more comprehensive and in-depth review about the geographical distribution, traditional uses, chemical constituents and pharmacological activities as well as safe and toxicity of Gynura species has been summarized, hoping to provide a scientific basis for rational development and utilization as well as to foster further research of these important medicinal plant resources in the future.
MATERIALS AND METHODS: A review of the literature was performed based on the existing peer-reviewed researches by consulting scientific databases including Web of Science, PubMed, Elsevier, Google Scholar, SciFinder and China National Knowledge Infrastructure.
RESULTS: Many of the Gynura species have been phytochemically studied, which led to the isolation of more than 338 compounds including phenolics, flavonoids, alkaloids, terpenoids, steroids, cerebrosides, aliphatics and other compounds. Pharmacological studies in vitro and in vivo have also confirmed the various bioactive potentials of extracts or pure compounds from many Gynura plants, based on their claimed ethnomedicinal and anecdotal uses, including antioxidant, anti-inflammation, anticancer, antidiabetic, antihypertension, antibacterial and other activities. However, pyrrolizidine alkaloids (PAs) pose a threat to the medication safety and edible security of Gynura plants because of toxicity issues, requiring the need to pay great attention to this phenomenon.
CONCLUSION: The traditional uses, phytochemistry and pharmacology of Gynura species described in this review demonstrated that these plants contain a great number of active constituents and display a diversity of pharmacological activities. However, the mechanism of action, structure-activity relationship, potential synergistic effects and pharmacokinetics of these components need to be further elucidated. Moreover, further detailed research is urgently needed to explain the mechanisms of toxicity induced by PAs. In this respect, effective detoxification strategies need to be worked out, so as to support the safe and reasonable utilization of Gynura plant resources in the future.
AIM OF THIS STUDY: This study aimed to investigate the potential toxicity effects of A. hierochuntica in pregnant Sprague-Dawley rats and their developing foetuses.
MATERIALS AND METHODS: Experiments were conducted in accordance to the Organisation for Economic Co-operation and Development guideline 414. Animals were randomly divided into four groups (n = 10 females per group): negative control (received the vehicle only), experimental animals received 250, 500, and 1000 mg/kg A. hierochuntica aqueous extracts (AHAE), respectively. Treatment was administered daily by oral gavage from gestational day (GD) 6-20, and caesarian section performed on GD21.
RESULTS: There were significant reduction in the corrected maternal weight gain of dams and body weight of foetuses in the lowest and highest dose of AHAE-treated animals compared to the control. These findings were associated with the increase in anogenital distance index and multiple congenital anomalies observed in some of the offspring. On the other hand, rats treated with 500 mg/kg showed higher embryonic survival rate with absence of significant treatment-related effect.
CONCLUSION: Findings showed that highest and lowest doses of AHAE have prenatal toxicity effects in SD rats. Therefore, AHAE is potentially harmful to the developing foetuses especially when consumed during the period of implantation and organogenesis. As for the rats treated with 500 mg/kg AHAE, there was no significant treatment-related effect. Hence, we postulate that this finding suggests that the disruption on the hormonal regulation could have been compensated by negative feedback response. The compensated effects of AHAE at 500 mg/kg and the presence of lowest observed adverse effect level (LOAEL) at 250 mg/kg has resulted in a non-monotonous dose response curve (NMDRC), which complicates the determination of the value of no-observed-adverse effect level (NOAEL).